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One of the most frequent questions I’m asked is whether it’s acceptable to end a sentence with a preposition.

I know many of you were taught that you shouldn’t end a sentence with a preposition, but it’s a myth. In fact, I consider it one of the top ten grammar myths because many people believe it’s true, but because nearly all grammarians disagree, at least in some cases (1, 2, 3, 4, 5, 6, 7, 8).

So before I lose you, let's back up. What is a preposition?

What Is a Preposition?

A preposition is a word that creates a relationship between other words. It's been said that prepositions often deal with space and time (1), which always makes me think of Star Trek. For example, the prepositions “above,” “by,” and “over” all say something about a position in space; the prepositions “before,” “after,” and “since” all say something about time.

When Can a Sentence End with a Preposition?

Here's an example of a sentence that can end with a preposition: What did you step on? A key point is that the sentence doesn't work if you leave off the preposition. You can't say, “What did you step?” You need to say, “What did you step on?” to make a grammatical sentence.

I can hear some of you gnashing your teeth right now, while you think, “What about saying, 'On what did you step?'” But really, have you ever heard anyone talk that way? I've read long, contorted arguments from noted grammarians about why it's OK to end sentences with prepositions when the preposition isn't extraneous (1), but the driving point still seems to be, “Nobody in their right mind talks this way.” Yes, you could say, “On what did you step?” but not even grammarians think you should. It sounds pedantic.

When Can't You End a Sentence with a Preposition?

But, you can't always end sentences with prepositions. When you could leave off the preposition and it wouldn't change the meaning, you should leave it off. Here is a cell phone commercial that gets on my nerves.

[Where you at?]

For the purposes of today’s discussion, let’s ignore the fact that they left out the verb “are” because I’ve definitely heard people ask, “Where are you at?”

The problem is that “Where are you at?” doesn't need the preposition at the end. If you say “Where are you?” it means the same thing. So the "at" is unnecessary. You should leave it off.

Unnecessary Prepositions

The problem with unnecessary prepositions doesn't happen just at the end of sentences. People often throw extraneous prepositions into the middle of sentences, and they shouldn't (2). Instead of saying “Squiggly jumped off of the dock,” it's better to say “Squiggly jumped off the dock.” You see? You don't need to say “off of the dock”; “off the dock” says the same thing without the preposition.

Another example is “outside of” when “outside” by itself would do just fine. You should say, “He's outside the door,” not, “He's outside of the door.”

Sentences Can End with Prepositions from Phrasal Verbs

So far, my examples of prepositions at the end of sentences have all been questions. Lest you think they’re a special case, we’ll look at some sentences that aren’t questions.

English has a type of verb called a phrasal verb. These are verbs made up of multiple words, and one is always a preposition. “Cheer up,” “run over,” “log on,” and “leave off” are all examples of phrasal verbs, and often sentences that use phrasal verbs end with a preposition:

I wish he would cheer up.

You should leave it off.

Those are perfectly acceptable sentences.

Other Sentences Can End with Prepositions Too

It’s also OK to end a sentence with a preposition sometimes even when you aren’t using a phrasal verb. For example, although you could rewrite the following sentences to avoid ending them with a preposition, you don’t need to.

She displayed the good humor she’s known for. (Could be rewritten as “She displayed the good humor for which she’s known.”)

I want to know where he came from. (Could be rewritten as “I want to know from where he came.”)

Cover Letter Grammar

I said you don’t need to rewrite those sentences, but because of the prevalent myth that it’s wrong to end sentences with prepositions, there are times when you should avoid doing it even though it isn’t wrong. For example, when you’re writing a cover letter to a potential employer, don’t end a sentence with a preposition. The person reading the letter could see it as an error. I always recommend following the most conservative grammar rules in job applications. I’d rather be hired than lose out on an opportunity because my grammar was correct--but perceived as wrong.

But once you're hired and you’re in a position to have a discussion about grammar, don’t be afraid to end sentences with prepositions as long as the preposition isn’t unnecessary. Just be ready to show your boss a good style guide or this Web page and do your part to dispel one of the top ten grammar myths.